RALEIGH — Police charged a 21-year-old man Thursday with molesting at least four dogs at the Wake County animal shelter where he worked as a volunteer.

Detectives arrested the man after they learned from a tipster that he posted photos on the Internet of himself molesting the animals.

Seadon Collins Etienne Henrich of Steves Drive in Zebulon was charged with four felony counts of crime against nature and three felony counts of disseminating obscenity, according to arrest warrants filed Thursday at the Wake County Magistrate’s Office.

Police think the incidents occurred over 18 months, ending Nov. 18, 2012, at the Wake County Animal Center on Beacon Lake Drive in East Raleigh.

Wake County Magistrate J.D. Saferight said Henrich first began working at the animal shelter as a volunteer and was eventually hired full time. He left the agency but returned as a volunteer who worked by himself at night, alone with the dogs.

Investigators say Henrich on at least four occasions “willfully and feloniously did commit the abominable and detestable crime against nature with a DOG,” according to the arrest warrants.

The police say Henrich then went to a website that features bestiality and posted at least three photos of himself “engaged in a sex act with a dog,” arrest warrants stated.

“I have been here 31 years and I thought I had seen everything, but this is new,” Saferight said.

Officials at the animal center could not be reached for comment Thursday.

Henrich was placed in the Wake County jail early Thursday afternoon under $70,000 bail. If he does post bail, he has been ordered to not go into any public or private facility where animals are kept.